Operating mechanism job eleyating-tbttcxs



J. L. CHESNUTT.

OPERATING MECHANISM FOR ELEVATING TRUCKS.

APPLICATION FILED AUG. I8, I919.

1 ,353,564, Patented Sept. 21,1920,

2 SHEETS-SHEE'I I.

//v VENTOH: JL. C'HESJY'Z/TT Bad MW Hull/ll J. L'. CHESNUTT. OPERATINGMECHANISM FOR ELEVATING TRUCKS.

.7 v A 0 R NE 1% EH 24 v0 7 h ML J w m B m. D m -dofl A 6 3 5 1 &0 *WQUNITED sTATes Parent OFFICE.

JOHN LOUCIEN onnsnnrr, or run CASTER & TRUCK COMPANY, or MISSOURI.

Tm CLL Specification of Letters Patent.

MISSOURI, ASSIGNOR TO THE SERVICE CITY, MISSOURI, A CORPORATION OFOPERATING MECHANISM FOR ELEVATINGTTRUGKS.

Patented Se t. 21, 1920.

Application filed August 18, 1919. Serial No. 318,130.

T 0 all whom it may concern: I

Be itknown that I, JOHN LOUCIEN CHES- NUTT, a citizen of the UnitedStates of Amervating truck.

A further object of this invention is to provide an improved operatingmechanism for elevating trucks wherein the load is al ways under perfectcontrol of the operator at all times during the raising or loweringoperation; wherein the load is prevented from descending with a olt orgar; and

wherein in'ur to the o erator throu h accidental flying up of the handleis elimi T nated; the descent of the load being automatically checkedwhenever positive pressure on the handle by the operator is terminated.

A further object of this invention to provide improved means foradjusting the connection between the operating mechanism and thevertically movable truck frame.

A further object of this invent-ion is to provide improved means toinitiate the downward movement of the load.

With these and other objects in view, my invention consists in theconstruction, arrangement and combination of elements hereinafter setforth, pointed out in my claims and illustrated by'the accompanyingdrawing, in which 7 Figure 1 is a front elevation of an elevating truckequipped with my improved operating m'echanism. Figs. 2 and 3 arecross-sections on the lines 2-2 and 33 respectively of Fig. 1, on anenlarged scale. Fig. 4 is a side elevation, partly in section,illustrating the truck and operating mechanism, a portion of the handlebeing broken away. Fig. is a front elevation of the tripping mechanism.Fig. 6 is a horizontal section taken substantially on the line 66 of1,the cam wheels being omitted. Fig. 7 is a vertical section takensubstantially on the line 'T-7 of Fig. at. In all of to and between thebrackets 15, 16.

the views the parts are shown in the raised position.

In the construction of the device and mechanism as shown the numeral 10designates generally a lower truck frame having suitable supportingwheels 11 adapted for contact with a tread surface. The numeral 12designates generally an upper or load carrying truck frame adapted forsupport on and vertical movement relative to the lows frame 10, suchvertical movement be ing accomplished by means of rollers 13 journaledin the upper frame 12 and adapted to travel on inclined tracks 14 formedon the lower frame 10. The upper frame is adapted to be elevated, and toelevate a load carried thereby, through a distance of substantiallythree inches, by forward movement on the lower frame, to the positionshown in the accompanying drawing. The construction and arrangement ofthe respec tive truck frames, other than above briefly outlined, isimmaterial, as my present invention relates to the mechanism foroperating the elevating devices, and procuring the vertical movementofthe upper or elevating truck frame.

Spaced brackets 15, 16 are fixed to and extend forwardly and slightlyupwardly from the forward member of the lower truck frame 10, and atongue bolt 17 is carried by said brackets, and arranged parallel withand spaced relative to the forward member of said frame. A. tongue yoke18 is provided and has end portions of its arms pivoted on the tonguebolt 17 adjacent l-L t1]: bular tongue member 19 is clamped in' theupper portion of the yoke 18 and extends a suitable distance therefromto adapt it.

for manual control in conveying the device from place to place on thesupporting wheels 11, and for other 'uses hereinafter to be made clear.7 A cross handle bar 20 is carried by the free end of the tongue member19.

L-shaped braces 21, 22 have their upper ends carried by the tongue bolt17, just outside the brackets 15, 16, thence extend downwardly and thenrearwardly toward the forward member of the lower truck frame 10, therearwardly extending portions of said braces being offset inwardlybetween their face ends as shown in Fig. 6. A bracket 23 is formed onthe central portion of the forward member of the lower frame 10 and eX-.tends forwardly beneath and between the brackets 15, 16, but is ofconsiderably less length than said last named brackets. A

L-shaped braces 21, 22, being arranged par allel with and directlybeneath the tongue bolt 17.

Two cam wheels, designated generally by the numerals 26, 27, are mountedfor rotary movement on the tongue bolt 17 between the arms of the yoke18, whilea grooved wheel 28 is also mounted on said tongue bolt, between said cam wheels, and is secured to the cam wheel2l6, which may bedesignatedas the lifting wheel, the cam wheel 27 ilarly being thelowering wheel. The lifting cam wheel 26 is formed on its outer with acircumferentially arranged wedge-shaped cam 29, which extends throughoutapproximately one-half of the periphery. of said wheel; and the'loweringcam wheel 27 is formed on its outer face with a circumferentiallyarranged wedgeshaped cam 30 which extends throughout approximatelyone-fourth of the periphery of said wheel. The widest point of the cam30 corresponds in width to the widest point of the cam 29; that is tosay, the cam 30 advances the same amount as the cam 29 in one-half thelineal space, and is consequently of twice the pitch. The lifting camwheel 26 is formed with a plurality of spaced lugs 31 on its periphery,in this instance four in number, and the lowering cam wheel 27 is formedpreferably with a single lug 32 on its periphery. Each of the lugs 31,32 is formed with one straight face, which is arranged substantiallyradially of the wheel on which. the lug is formed, adapted to be engagedby a pawl to produce rotary movement of the wheel. A controlling shaft33 is journaled in and longitudinally of the yoke 18, extends within andthrough the tubular tongue member 19, and projects from the upper orfree end thereof, having a thumb piece 34 fixed to its upper projectingend. Pawls 35, 86 are mounted for rectilinear reciprocation in the yoke18, on opposite sides of the shaft 33 and directly opposite and adaptedfor engagement with the lugs of the respective cam wheels 26 and 27. Thepawls 35, 36 are pressed to operative'engagement by coil springs 37, 38respectively. The pawls 35 36 also are formedwith fingers, 39, 40respectively, pro jecting inwardly toward the shaft 33, which is formedor providedwith a cam disk 41 -engaging beneath said fingers, and soarranged that but one of the pawls can be in operative engagement at agiven timeyone or both of the pawls at all times being held by said camdisk out of operative engagement with the adjacent cam wheel, againstthe influence of its spring. e

A bracket 42 is fixed to and projects for- Wardly and upwardly from thecentral portion of the forward member of the upper truck frame 12, and adraft cable 43 is fixed at one end to said bracket, as by means of a pinor bolt 44. The cable 43 extends forwardiy over the grooved wheel 28 andhas its opposite end extended through a peripheral hole 45 (Fig. 7 insaid wheel, and secured to said wheel in any suitable manner as bybabbittingr A bolt 46 passes through the grooved wheel 28 and throughanarouate slot 47 in the lifting cam wheel 26 and is secured by a nut 48.A boss 49 is formed on the outer face of the cam wheel 26 sursuchmanneras to apply strain on the cable 43, the nut 48 contacting with theinclined face of said boss. It is the purpose of this construction toprovide means for adjusting the grooved Wheel relative to the liftingcam wheel so as to adjust the effective length of the draft cable, inorder that the vertically movable upper truck frame may be in the properposition to correspond to the various positions of thelifting cam. henstrain is applied on the cable 43 in the lifting operation the inclinedface of the boss 49 prevents movement of the connecting bolt 46 andtends to prevent disarrangement of the adjustment of the parts. Thewheel 28 also is formed with a boss, 49", inclined oppositely to theboss 49, so that strain is applied evenly on the bolt 46. I

The cam wheels 26, 27 and grooved wheel 28 are formed with extended hubswhich substantiallyfill the space on the tongue, bolt 17 between thearms of the yoke 18. A

sleeve 50 is mounted on the tongue bolt 17,

within the hub of the cam wheel 27, and is of slightly greater lengththan said hub, to prevent binding of said wheel in certain of itsmovements. The hubs of the wheels 26 and 28, together with the sleeve50, fill the space on the tongue bolt 17 between the arms of the yoke18. The grooved wheel 28 is formed with an annular face'in frictionalcontact with the inner face of the and spaced apart a distancecorresponding substantially to the horizontal distance beof the brakemember 51 and is secured thereto by'a vertical pivot boltor screw 54, sothat said brake shoe may oscillate slightly on a vertical axis toconform to irregularities which may occur in the cam surface with whichit contacts. The brake shoe 52 is substantially L-shaped and hasits'rear arm extending across the rear side of an arm of the brakemember 51 and formed with a longitudinal slot 55 (dotted lines Fig. 6)through which passes a screw 56 seated in the said arm of the brakemember. This connection permits the brake shoe to oscillate in order toautomatically adjust itself to any variation in the cam surface withwhich it contacts. It also permits a bodily adjustment of the brake shoelaterally, to compensate for wear and in order to secure the properspacing *of the brake shoes; such adjustment being accomplished by meansof an ad ust1ng screw 57 seated 1n the arm of the brake member andengaglng sa1d brake shoe, and provided at its outer end with a lock nut58 to secure such adjustment when made.

A spring 59 is wound on the hub of the lowering cam wheel 27 and securedat one end thereto as through the medium of a stud 59*, and has itsopposite end secured to the frame, preferably the inner face of themember 22 as at 59 The tendency of the spring 59 is to turn the loweringcam wheel 2'? rearwardly and to force its cam against the brake shoe 53and induce frictional contact between said members. Rearward strain onthe cable 43, due to weight of the load (the upper truck frame 12 andwhatever may be carried thereby), has tendency to turn the lifting camwheel 26 rearwardly and to force its cam against the brake shoe 5 Therear ward tendency of the two cam wheels causes a wedging of the twocams between the two brake shoes, limiting such rearward movement andcausing a frictional engagement between the rims of the wheels 27 and28. It is apparent that further rearwardmovement of either cam wheel,under the causative forces above set forth, can occur only when theother of said wheels is forcibly and positively rotated in the oppositedirection, or forwardly, thus relieving pressure of its cam on thecorresponding brake shoe; and that as soon as such positive forwardrotation ceases, the tendencies toward rearward rotation of both camwheels will again counteract each other, by wedging the wheels betweenthe brake shoes, and the parts will remain in they position where left.

Forward rotation of the lifting cam wheel 26, through engagement of thepawl 35 with either of the lugs 31 thereof, permits a rearward movementof rotation of the lowering cam wheel 27, by relieving pressure on thebrake member as above stated, and such rearward rotation of the camwheel 27 causes alateral sliding movement of the brake member 51 on thespindle 25 through action of its cam on the brake shoe 53. This lateralmovement of the brake member 51 retains the brake shoe 52 in itsapproximate position relative to the cam of the forwardly moving wheel26, ready to engage and prevent opposite movem nt of said cam when theforce causing the forward movement is released. It is apparent thatforward rotation of the lifting cam wheel 26, starting with the truck inits lowered position, will have the effect of raising or elevating theupper truck frame 12, and its load, relative to the supporting frame 10,by winding the cable 43 on the grooved wheel 28 attached to said liftingcam wheel, the rollers 13 of said upper frame rising on the inclinedways 14 of the lower frame.

Forward rotation of the lowering cam wheel 27, through engagement of thepawl 36 with the lug 32 thereof, permits a rearward rotary movement ofthe lifting cam wheel 26, by relieving pressure on the brake member aspreviously stated, and such rearward rotation of the lifting cam wheelcauses a lateral sliding movementvof the brake member 51 on the spindle25 through action of its cam on the brake shoe 52. It is apparent thatsuch rearward rotary movement of the lifting cam wheel 26. startmg withthe truck in its elevated position, permits a descent by gravity of theupper truck frame 12 on the frame 10.

The cam disk 11 is turned for raising and lowering the pawls 35, 36 byoperation of the controlling shaft 33, manually operable by the thumbpiece which may be turned laterally in one direction to permit operativeengagement of one of said pawls and in the other direction to permitoperative engagement of the other, and preferably has indications on itsrespective sides, such as the words Up and Down, to guide the operator.Nhenthe thumb piece 3% projects forwardly in the position shown in Fig.4the disk -21 is in such position as to hold out of operative enga ementboth of the pawls 35, 36, and the tongue may then be oscillated on thetongue bolt 17 without any e fect upon the cam wheels and otheroperatmechanism. This -is desirable when hauling the truck from place toplace or when it is not desired to employ the raising and loweringmechanism. A lug 60 may project forwardly from the upper end ofthetongue member 19, immediately below the thumb piece 34:, being ofgreater length than saidthumb piece, so as to protect said piece frominjury in case the end of the tongue falls to the floor when said pieceis in extended position.

A rod 61 is mounted transversely between the rear end portions of theL-shaped memhers 21, 22, between the bolt 24: and spindle .25, and a lugorprojection 62 on the rear of theyolre shaped brake member 51 slidably.engages said rod. It is the function of this construction to preventtipping of the sliding brake member and to hold the brake shoes 52, 53in their proper positions; I The parts are so arranged that the first ofthe lugs 31 of thelifting cam Wheel 26 is the top of the wheel and justin front ofthe position of the pawl 35, when the upper truck 12 is inits lowermost position.

thetongue or handle by the operator, causing a forward rotation of thelifting wheel 26 with the result previously explained. The tongue orhandle may be moved through an arc of approximately ninety degrees withthe pawl in engagement with the first or foremost lug 31 if desired; butif the load is heavy it will be found more convenient, and greaterpurchase on the handle obtained by the operator, if he will move thetongue successively through shorter arcs, engaging the pawl 85successively with the lugs 31, which are here four in number, until thelifting cam has been moved through an arc of approximately one-hundredeighty degrees, the effective length of the cam. It will be observedthat it requires at least two movements of the tongueto accomplish thelifting operation, as the lifting cam must be turned a half revolution,while the movement of the tongue is restrictedto approximately a ninetydegree sweep at one time, starting from the approximate verticalposit-ion. WVhen it is desired to lower the truck from the elevatedposition the thumb piece is turned to the opposite side to permit theengagement of the pawl 36 with the lug 32 of the lowering cam wheel 27,which in this position of the devices is approximately at the top of thesaid wheel. Then the tongue or handle is moved forwardly and downwardlyfrom verticalto approximately horizontal position, with the resultpreviously described. As the pitch of the cam of the lowering wheel isgreater than that of the lifting wheel, extending through an effectivelength of but ninety degrees circumferentially of its wheel, it followsthat a single movement of the tongue or handle through an arc of ninetydegrees will accomplish the lowering operation. Hence the necessity of 7of raising or of lowering the upper truck,

that pressure is relieved'from the handle and positive forward movementof one or the other of the cam wheels ceases, on account of the factthat the normal rearward tendencies of the two wheelscounteract eachother and force the cams into frictional contact with the two sides ofsaid brake member. Because of this automatic braking effect the load maybe handled without danger to the operator from the handle flying up andstriking him as sometimes happens in the use of other devices when theweight of the load accidentally gets beyond his, control during theraising or lowering operation.

A combined foot rest and handle stop preferably is employed, comprisinga hub or collar 68 secured to one end portion of the tongue bolt 17 andformed with a projection 64 extending over the upper end of the adjacentL shaped member 22 and bracket 16 and behind the adjacent arm of thetongue yoke 18. This projection limits rearward movement of the handle,preventing its falling rearwardly against the load or the cable 43; andalso affords a foot rest for the operator in applying pressure to thehandle to initiate the raising of a load. It is desirable that when theupper frame is in its elevated position the rollers 13 shall rest on ahorizontal plane beyond the upper ends of the inclined ways 11, as shownin Fig. 1. As this normally relieves the strain on cable 43 throughforce of gravity on the elevated load, it becomes necessary to provide ameans for starting the load (upper truck frame) rearwardly, and forcingthe rollers 13 upon the inclined planes 14, when the lowering operationis initiated. A lever 65 is fulcrumed at its lower end on the bolt 24and projects upwardly in front of the position. occupied by the forwardmember of the upper truck frame 12 when in raised position, as shown inFig. 2. The lever 65 is bifurcated at its lower end and straddles an arm66 which also is pivoted at its lower end on the bolt 2% and extendsforwardly and upwardly in front of said lever. A pair of pawls 67, 68are provided and are mounted on opposite sides of the lever 65 and arm66 and pivoted intermediate of their ends to said arm. At their forwardends the pawls 67, 68 are formed each with an upstanding tooth 69adapted to engage between teeth '70 formed on a portion of. theperiphery of the lowering cam wheel 23', said teeth being in positionfor engagement by said pawls when the parts are in the elevatedposition. ()ne of-the pawls 6?, 68 is slightly longer than the other, byan amount correspond'ng appro: e to one-half the distance between teethof the cam wheel, so thatone of said pawls is always ready for,engagement of its teeth between teeth of the wheel, and said p wls areaffected and moved promptly upon movement of retation of said cam wheel,as will hereinafter be explained. Rear portions of the pawls 67, 68overlie abutments 71 formed on opposite sides of the lever 65, andsaid-pawls are formed with shoulders 72, in substantially verticalplanes, but inclined slightly to the rear from such planes, whichshoulders are adapted to engage forward faces of the abutments '71 andexert pressure thereon at times. The pawls 67, 68 are turned upwardly attheir rear ends and have the rear faces of such upturned portions formedon planes inclined somewhat to the rear. A stop 73 is carried by thecross member of the lower truck frame 10 and is vertically adjustable onthe forward face thereof, being formed with a vertical slot through wiich extends a bolt 74 or other securing member also extending throughsaid frame member. The stop 73 is beveled or inclined on its forwardface to correspond to the inclination of the rear end of the pawls 67,68 and is adapted for contact thereby. The stop 7 3 may be adjustedvertically and thereby, because of its inclination, determine theposition of the pawls 67, 68 on their pivots, and consequently thedegree of contazt of the shoulders 72 with the lever abutments 71. Thenthe lowering operation of the mechanism is initiated, the first movementof the wheel 27, under the influence of the pawl 36, causes a slightrearward movement of one or the other of the pawls G7, 68, dependingupon which of said pawls is then in posi-, tion for engagement of itstooth 69 with a tooth of the said wheel. Such movement of the pawls istransmitted to the lever 65 through contact of the shoulder T with anabutment 71, and the upper end of the levereXerts rearward pressure onthe top frame 12 to cause it to start rearwardly and reach the inclinedways 14. hen the upper end of the lever 65 has moved suliiciently toaccomplish this result the shoulder or shoulders 72- slip over the topsof the abutments T1, and further movement of the "am wheel has no effectupon the said lever. A coil spring 75 is fixed to the forward member ofthe lower frame 10 and to the lever (35 and is adapted normally to holdsaid lever rearwardly and prevent forward movement of the upper endthereof. The arm 66 is pawls 6?, 68.

formed near its rear end with a rearwardly projecting lug 76 extendingwithin the .bifurcation of the lever 65 and adapted to engage the upperend of said bifurcation to limit forward oscillation of the arms andllhen the top frame 12 is elevated it engages the upper end of lever 65and moves it forwardly, putting the spring '75 under tension, andtirowing the pawls 67, 68 forwardly to position for en gagement with theteeth of the cam wheel when the same is revolved for the loweringoperation.

On the rear portions of the brackets 15, 16 are formed shoulders 78which are adapt ed for engagement by the forward member of the uppertruck frame 12, and serve as stops to limit forward movement of the saidframe in the elevating operation. Lugs 77 are formed on side margins ofthe lower truck frame 10 and extend upwardly within the upper truckframe 12, to prevent lateral movement of the upper relative to the lowerframe. 7

The sleeve 50 prevents friction between the=hub of the cam wheel 2'? andthe adjacent arm of the yoke 18, such as might overcome the effect ofthe spring 59, particularly where there is a side pull on the cable 43as where the truck is on an inclined surface. 7

Particular attention is drawn to the fact that the load is always underperfect con trol of the operator, and will not descend with a jolt evenif his hands should be removed from the handle. The spring-pressed camwheel 2'7, which may be termee a locking as well as a lowering wheel,serves to force the brake devices against the cam of the lifting wheel26 in such manner as to prevent downward movement of the load except atsuch times as positive pressure is exerted to turn said wheel 27forwardly. The operator is enabled to lower the load as slowly and asgently as he pleases, or he can let it down with one swift movement ofthe tongue, and little exertion is required. The lifting operation alsois facilitated by the provision for employing several strokes of thehandle, starting at favorable angles, if desired.

lVhile I have illustrated and described this mechanism as being appliedto elevating trucks and employed in the operation of raising andlowering such devices, I do not wish to be understood as limited to itsuse in this connection, as I consider this invention anautomatic safetyclutch which may be used in many devices where the raising and loweringoperations are employed; and many modifications and alterations from theform herein shown and described may be employed, within the scope of theappended claims, without departing from my invention.

It should be noted particularly that weight of the load, acting throughthe cable 43 and applying strain rearwardly on the cam wheel 26, tendsto make a wedge out of the wheels-26 and 27 which acts between the brakeshoes 52 and 53, the friction between the'inner face of the wheel'28 andthe inner face of wheel 27 compels the latter wheel to turn rearwardlyvith waeel 26. Pressure of the cam of wheel 26 on the shoe 52, act ingthrough the sliding bra-ire member 51, causes the shoe 53' to press onthe cam of wheel 27 in such manner as to tend to turn said wheelforwardly; but the friction between wheels 28 and 27, together with theaction of spring 59, is great enough to prevent such forward turning ofwheel unless additional force is applied through the handle to turn thewheel 2. forwardly in order to accomplish lowering of the load. In otherwords the parts are so arranged that the load cannot be lowered withouta mentally selected acton the part of the op erator in properlypositioning the control device 34 and then moving the handle forwardlythrough an arc to accomplish such end. a g

The wheel 28 preferably is beveled on one margin and fits within aninclined flange 79 on cam wheel 27, to provide'additional frictionalengagement between said wheels, so that the cam wheel 27 will not beturned forwardly under the pressure of heavy loads. I

I claim as my invention 1, An elevating truck, wheeled truck frameformed with incline ways, an elevating frameformed with roll ers adaptedto travel 011 said ways, a rotary lifting member carried by said truckframe, a flexible member secured to said elevating frame and alsosecured to and adapted to be wound on said lifting member, said liftingmember being formed with a wedge-shaped cam on one of its faces, a brakemember slidably carried by said truck frame and adapted for engagementwith said cam, and means for normally maintaining said brake member infrictional engagement with said cam, to prevent reverse rotation of saidliftin member.

2. in elevating truck, comprisiin a wheeled truck frame formed withinclined ways, an elevating frame provided with rollers adapted totravel on said wow a rotary comprising v a lifting member carried bysaid truck frame,

a flexible connecting member secured to said elevating frame and adaptedto be wound on said lifting member, said lifting member being formedwith a. wedge-sh ped cam on one of its faces, a brake member slid ablymounted on said truck frame and adapted for engagement with said cam,and a rotary lowering member carried by said truck frame, said loweringmember being formed with a Wedgeshaped cam in engagement with said brakemember and normally tending to hold the same in frictional 'engagementwith the cam of the lifting member.

3. An elevating truck, comprising a wheeled truckframe formed withinclined ways, an elevating frame on said truck frame and adapted to beelevated by for ward travel over said ways, a rotary lifting membercarried by said truck frame, a

flexible connecting member secured o said elevating frame and adapted tobe wound on said lifting member, said lifting member being formed with awedge-shaped cam on one face, a rotary lowering member carried by saidtruck frame and formed with a wedge-shaped cam opposite to thefirstnamed cam, a-brake device slidably carried by the truck frame andembracing said lifting and lowering members and'adapted for simultaneouscontact with both of said cams, and yielding pressure devices tending toturn said lowering device in such manner as to apply pressure of its camon said brake device and thereby produce braking effect on the cam ofthe lifting member.

4:. An elevating truck, comprising a wheeled truck frame formed withinclined ways, an elevating frame on said truck frame adapted to beelevated by forward travel on said ways, a rotary lifting member carriedby said truck frame, a flexible connecting member secured to saidelevating frame and adapted to be wound on said lifting member, saidlifting member being formed with a wedge-shaped cam on one face, arotary lifting member carried by said truck frame and formed with awedge-shaped cam, a brake device 'slidably carried by the truck frame,embracing said lifting and lowering members and adapted for simultaneouscontact with said cams, yielding pressure devices tending to turn saidlowering device in such manner as to apply pressure of its cam on saidbrake device and thereby produce braking effect on the cam of thelifting member, ahandle member adapted for oscillation on a horizontalaxis,

and manually controlled devices on said. handle member for selectivelyengaging and imparting rotation to said lifting and lowering members.

5. An elevating truck, comprising a wheeled truck frame formed withinclined ways, an elevating frame on said truck frame adapted to beelevated by forward travel on said ways, a rotary lifting meming memberand formed with a cam on its outer face, a brake device slidably carriedby said truck frame, embracing said lifting and lowering members andadapted for simultaneous contact with the cams thereof, yieldingpressure devices tending to turn said lowering device in such manner asto apply pressure of its cam on said brake device and thereby producebraking effect on the cam of the lifting member, said lifting andlowering members being formed with peripherally projecting lugs, ahandle member mounted at the forward end of the truck frame and adaptedfor oscillation on a horizontal axis, and pawls carried by said handlemember and adapted for selective movement under manual control topositions for engaging the lugs of said lifting and lowering members,whereby said members may be rotated by forward and downward movement ofsaid handle member.

6. An elevating truck, comprising a wheeled truck frame formed withinclined ways, an elevating frame on said truck frame adapted to beelevated by forward travel on said ways, cam wheels mounted for rotationside by side at the forward end of said truck frame and adapted for userespectively in the lifting and lowering operations, said wheels beingformed with wedge-shaped cams on their outermost faces, a brake deviceslidably carried by said truck frame, embracing said cam wheels andadapted for simultaneous contact with the cams thereof, yieldingpressure devices tending to turn the lowering cam wheel rearwardly so asto apply pressure of its cam on said brake device and thereby producefrictional contact of said brake device with the cam of the lifting camwheel, the lowering cam wheel being formed with a peripheral projectinglug and the lifting cam wheel being formed with a plurality of spacedprojecting lugs, a handle member mounted at the forward end of the truckframe and adapted for oscillation on atransverse horizontal axis, andpawls carried by said handle member and adapted for selective engagementwith the lugs of the respective cam wheels, whereby said members may berotated-by forward and downward movement of said handle member, the camof the lowering cam wheel having a considerably steeper pitch than thecam of the lifting wheel.

7. An elevating truck, comprising a wheeled truck frame formed withinclined ways, an elevating frame provided with rollers adapted totravel on said ways, cam wheels mounted for rotation side by side at theforward end of the truck frame and adapted for use respectively in thelifting and lowering operations, said wheels being formed withwedge-shaped cams on their outermost faces, a brake device slidablycarried by said truck frame, embracing said cam wheels and adapted forsimultaneous contact with the cams thereof, a grooved wheel fixed to thelifting cam wheel, a cable fixed .to the elevating frame and also fixedto and adapted to be woundon said grooved wheel, a handlemounted foroscillation at the forward end of said truck frame, and

means carried by said handle for selective engagement with and rotationof said cam Wheels. 7

8. An elevating truck, comprising a wheeled truck frame formed withinclined ways, an elevating frame on said truck frame and adapted to beelevated by forward travel on said ways, cam wheels mounted for rotationside by side at the forward end of the truck frame and adapted for userespectively in the lifting and lowering operations, said wheels beingformed with wedge-shaped cams on their outer most faces, a brake deviceslidably carried by said truck frame, embracing said cam Wheels andadapted for simultaneous c011- tact with the cams thereof, a groovedwheel secured to the lifting cam wheel, a cable fixed to the elevatingframe and also fixed to and adapted to be wound onsaid grooved wheel,the connections of said grooved wheel to said lifting cam wheel beingcircumferentially adjustable to adjust the effective length of saidcable relative to said cam wheel, a handle mounted for oscillation atthe forward end of said truck frame, and means carried by said handlefor selective engagement with and rotation of said cam wheels.

9. An elevating truck, comprising a wheeled truck frame formed withinclined ways, an elevating frame on said truck frame and adapted to beelevated by forward travel on said ways, cam wheels mounted for rotationside by side at the forward end of said truck frame and adapted forforward rotation respectively for the lifting and lowering operations,said wheels being formed with wedge-shaped cams on their outermostfaces, a brake device slidably carried by said truck frame and embracingsaid cam wheels, said brake device being formed with opposed brake shoesadapted for simultaneous contact with the cams of said wheels,connections between the lifting cam wheel and the elevating frame, andmanually controlled means for selectively rotating said cam wheels.

10. An elevating truck, comprising a wheeled truck frame, an elevatingframe on said truck frame and arranged to be elevated by forwardmovement relative thereto, earn wheels mounted for rotation side by sideat the forward end of said truck frame and adapted for forward rotationrespectively for the lifting and lowering operations, said. wheels beingformed with wedgewheels, connections between the lifting cam' wheel andthe elevating frame, and manu ally controlled means for selectivelyrotating said cam. wheels. Y r

11. An elevating truck, comprising a wheeled truck frame, an elevatingframe on said truckframe andv arranged to be elevated by forwardmovement relative thereto, cam wheels mounted side by side at theforward end of said truck frame and adapted for forward rotationrespectively for the lifting and lowering operations, said wheels beingformed with wedgeshaped cams on their outermost faces, a brake deviceslidably carried bysaid truck frame and embracing said cam wheels, saidbrake device being formed with inclined brake shoes contacting. therespective cams of said wheels, one of said brake shoesbei ng adjustableto vary the distance between them, connections between the lifting camwheel and the elevating. frame, and manually controlled means forselectively rotating said ca wheels Am elevating truck, comprising awheelcd'truck frame, an elevating frame on said truck frame arranged tobe elevated by forward movement relative thereto, cam wheels mounted:side by side at the forward end of said truck frame and adapted forforward rotation respectively for the lifting and lowering, operations,said wheels being formed with wedgeshapcd cams on their outermost faces,a brake device slidably carried by said truck frame and embracing andadapted for simultaneous contact with the cams of said wheels,connections between the lifting ca m wheel and the elevating frame, saidcam wheels being formed with. projecting lugs, a handle member pivotedto the forward end of said truck frame, springpressed pawls carried bysaid handle member,.each of which is adapted for engagement at timeswith lugsof one of said cam wheels, a cam plate mounted for oscillationon said handle member and serving to hold one or both of said pawls outof operative engagement, and means for manually controlling said camplate.

13. An elevating truck, comprising a wheeled truck frame, an elevatingframe on said truck frame arranged to beelevated by forward movementrelative thereto, cam wheels mounted at the forward end of said truckframe and adapted for forward rotation respectively for the lifting andlowering operations, said wheels being formed with cams on theiroutermost faces, a brake device carriedby said truck frame and held oneof said cam wheels to apply braking ber, each of said pawls beingadapted for engagement with lugs of one of said. cam wheels, a shaftmounted for oscillation in said handle member, a cam plate on said shaftengaging and serving to hold one or both of said pawls out of operativeengagement, and a thumb piece on said shaft.

14i. An elevating truck, comprising. a wheeled: truck frame, anelevating frame on said truck frame arranged to be elevated by forwardmovement relative thereto,- spaced brackets fixed to and projectingforwardly from the front end of said truck frame, a rod carried. bysaid: brackets, a handle member formed with a yoke pivoted on said rod,a pair of cam wheels mounted on said rod within said yoke, a brakedevice carried by said truck frame and acted upon by one of said camwheels to apply pressure to the other, connections between the lattercam wheel and the elevating frame, pawls carried by said yoke andadapted for selective en gagement with said cam wheels, and meanscarried by said handle member for manipulating. said pawls.

15. An elevating truck, comprising a wheeled truck frame, an elevatingframe on said truck frame arranged to be elevated by longitudinalmovement relative thereto, spaced brackets fixed to and projectingforwardly from one end of said truck frame, a rod carried by saidbrackets, ahandle member formed with a yoke pivoted on said rod, a pairof cam wheels mounted on said rod within said yoke, a brake deviceslidably carried by said truck frame and acted upon by pressure to theother thereof, connections between one of said cam wheels andtheelevating frame, pawls carried by said yoke and adapted for selectiveengagement with the cam wheels, a shaft extending lengthwise throughsaid handle member and between said pawls, a cam plate on said shaftadapted for engagement with said pawls to hold one or both out ofoperative engagement, and means on the opposite end of shaft formanually oscillating the same.

16. An elevating truck, comprising a wheeled truck fra ie formed withinclined ways, an elevating frame provided with rollers adapted totravel on said ways and be elevated by forward movement relative to saidtruck frame, a rotary lifting member carried by the forward end of saidtruck frame, a flexible connecting. member secured ,to said elevatingframe and secured to and adapted to be wound on said lifting member,

a rotary lowering member carried by said truck frame, means acted uponby said lowering member for preventing reverse movement of said liftingmember, and manually controlled means for selectively rotating saidlifting and lowering members.

17. An elevating truck, comprisin a wheeled truck frame formed withinclined ways, an elevating frame provided with rollers adapted totravel on said ways and be elevated by forward movement relative to saidtruck frame, a rotary lifting member carried by the forward end of saidtruck frame, a flexible connector secured to said elevating frame andadapted to be wound on said lifting member, a rotary lowering membercarried by said truck frame, means acted upon by said lowering memberfor normally preventing reverse movement of said lifting member,manually controlled means for selectively rotating said lifting andlowering members, and means connected with and operated upon by saidlowering member for initiating rearward movement of said elevating framewhen said lowering member is manually rotated.

' 18. An elevating truck, comprising a wheeled truck frame formed withinclined ways, an elevating frame provided with rollers adapted totravel onsaid ways and be elevated by forward movement relative to saidtruck frame, rotary lifting and lowering members carried by the forwardend of said truck frame, a flexible connector secured to said elevatingframe and adapted to be wound on said lifting member, means acted uponby said lowering member for normally preventing reverse rotation of saidlifting member, manually controlled means for selectively rotating saidlifting and lowering members, a lever fulcrumed at the forward end ofsaid truck frame and adapted to engage said elevating frame when inraised position, and a pawl pivoted to and adapted to impart rearwardmovement to said lever, said lowering member being formed with a seriesof teeth adapted for ,v

engagement by said pawl.

19. In a mechanism of the classdescribed, lifting and lowering membersmounted for rotation, means normally applying strain to tend to causerearward rotation of said lifting member, yielding pressure devicestending to cause rearward movement of said lowering member, means actedupon by said 7 lowering member tending to prevent rearward movement ofsaid lifting member, and manually controlled means for selectivelycausing forward rotary movement of said lifting and lowering members.

20. In a mechanism of the class described, lifting and lowering membersmounted for rotation, means normally acting to cause rearward rotationof each of said members,

braking means acted upon by said lowering member tending to preventrearward movement of said lifting member, and manually controlled meansfor selectively imparting forward rotary movement to said members, thelast named means also acting to release said braking means.

21. In a mechanism of the class described, lifting and lowering membersmounted for rotation side by side, said members being formed withinclined cams on their outermost faces, means normally acting to causerearward rotation of each of said members, braking means embracing saidrotary members and contacting the inclined cams thereof, forwardmovement of the respective cam wheels causing lateral sliding movementof said brake member in opposite directions, and manually controlledmeans for rotating said cam wheels in a forward direction.

22. In a mechanism of the class described, lifting and lowering membersmounted for rotation side by side, said members being formed withinclined cams on their outermost faces, spring-pressure devices tendingto cause rearward rotation of said lowering member, slidable brakedevices embracing said rotary members and contacting the inclined camsthereof, forward movement of the respective rotary cam members causingsliding movement of said brake device in opposite directions, andmanually controlled means for independently rotating said cam members ina forward direction.

28. In a device of the class described, a starting mechanism comprisinga lever fulcrumecl at one end, an arm pivoted on the fulcrum of saidlever, a pawl pivoted intermediate of its ends on said arm and extendingacross said lever, said lever being formed with an abutment, said pawlbeing formed with a shoulder adapted to engage said abutment and causeoscillation of said lever, and means for engaging and moving said pawl,the shoulder of said pawl being adapted to slip off of said abutmentafter said lever has moved the desired distance. 24. In a device of theclass described, a support, a lever fulcrumed at one end thereon, an armpivoted on the fulcrum of said lever, a pair of pawls of unequal lengthpivoted on said arm and crossing said lever, said lever being formedwith abutments on its opposite sides, said pawls being formed withshoulders adapted to engage said abutments and move said lever, meansfor engaging and moving said pawls, and a vertically adjustable inclinedstop on said support adapted for engagement by one end of said pawls.

Signed at Kansas City, in the county of Jackson and State of Missouri,this 23rd day of July, 1919.

JOHN LOUCIEN CHESNUTT.

